40 FPS seems to be pretty okay with those settings.
you could allways increase it to 60, but you would need to set general drawing quality to standart (can easily go to highest with background tho), and perhaps turn the super-sampling off, i noticed that super-sampling AA allways put a heavy weight on my graphics which is why i allways have it off (atleast in FFXIV)

my settings are the same as yours.
besides i have background drawing quality at highest, general drawing quality at standard, AA at 16xQ CSAA (i don't know if ATI is x16 tho), and S-SAA off.
i hit 60 FPS on the fields, and in towns and camps it varies between 60-30 (mostly due to the low load of GPU in towns )
with ambient occlusion i lose around 5-15 FPS on fields, so i can easily use it aswell without much hassle, but i prefer to have it off since i don't see a too big difference.

PS.:

indeed you're running the game rather well, i forgot that you seem to play on 3 screens